The adoption of France's framework energy bill, meant to fulfil President Francois Hollande's pledge to cut the share of nuclear energy in the country's electricity mix to 50 percent, has been pushed back to early 2015.
"It will be reviewed by parliament in the autumn and adopted in the spring of 2015," an official at Prime Minister Manuel Valls's office told Reuters on Friday, without elaborating on the reasons.
Earlier in the day French radio Europe 1 cited an adviser to Hollande as saying that the government will be 10 billion euros ($13.6 billion) short of funding for the bill's proposals.
The new law was initially expected to come into force before the end of 2014.
Segolene Royal, Hollande's fourth energy minister since the beginning of his mandate in 2012, has said she would unveil on June 11 the broad objectives of the bill, which she wants to use as leverage to boost renewable energies and economic growth.
No one at her office was available to comment on the latest delay.
The bill has been delayed repeatedly since 2012. It is expected to spell out how France, the world's most nuclear-reliant nation, intends to cut nuclear energy to 50 percent from 75 percent of its electricity production by 2025.
Energy ministry officials told a parliamentary hearing this year that the gradual closure of about 20 nuclear reactors would be required to meet Hollande's 2025 target if electricity consumption remains stable.
This seemed to contradict the view of Henri Proglio, the head of state-owned utility EDF, who said he expected electricity demand to rise because of population growth and that no reactor closure is needed.
Measures to boost renewable energy capacity, which has grown more slowly in France than in neighbours such as Germany or Spain, are also expected to be included in the law.
($1 = 0.7345 Euros)
(Reporting by Julien Ponthus; Writing by Michel Rose; Editing by David Goodman)